The present invention relates to a method for coating foil material of any shape with an injectable and pressable mass which stabilizes the foil material.
Generally, plastic foil materials are used today for many applications, such as covers or paneling, respectively. In the automobile industry, in particular, such foil material is used to panel the dashboards, the wheel wells extending into the interior, or other surfaces. For aesthetic reasons, the visible surface of the foil material is provided with decorative patterns, while the covered or not visible side of the single or multilayer foil material carries a stabilizing mass, which may also serve as a sound damping agent. Since the foil material is generally very thin, there exist great difficulties in applying the stabilizing mass onto the foil material with economically justifiable expenditures without thereby destroying the foil material.
It is a primary object of the present invention to provide a process for coating foil material which assures that the coating mass is applied to the foil without destroying the foil and which is independent of the shape of the foil material.
A further object of the present invention is to provide such a process under economically feasible conditions.
Additional objects and advantages of the present invention will be set forth in part in the description which follows and in part will be obvious from the description or can be learned by practice of the invention. The objects and advantages are achieved by means of the processes, instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing objects and in accordance with its purpose, the present invention, as embodied and broadly described, provides a process for coating foil material of any desired shape with an injectable and pressable mass which stabilizes the foil material comprising: pressing an initially planar heated foil material by means of a depressor against a movable mold member of an injection mold having a movable mold member and a stationary mold member, the injection mold having a shape which corresponds to the later shape of the foil material; then pulling the foil material against the surface of the movable mold member by subatmospheric pressure; subsequently moving the movable mold member toward the stationary mold member to provide a gap between the foil material and stationary mold member of the injection mold and slowly injecting the mass into the gap remaining between the foil material and the stationary mold member; and further closing the two mold members to finally distribute the mass over the foil material and press the mass to the required thickness.
One advantage of this process is that the foil material is brought to the desired shape in one process step by the use of subatmospheric pressure and is simultaneously coated with the mass. Since the coating is not applied by spraying, but by a combined injection and pressing process, the mass which is introduced into the injection chamber at low speed cannot damage the foil material. During the subsequent final pressing step, the mass is also distributed over the foil material relatively slowly so that here too there is no danger of damage. Use of the depressor furthermore provides for a simple structure of the injection molding device used for application of the process since this depressor in cooperation with the foil material produces the seal required for producing the subatmospheric pressure.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive of the invention.